Photonic heterostructures with Levy-type disorder: statistics of coherent transmission

We study the electromagnetic transmission $T$ through one-dimensional (1D) photonic heterostructures whose random layer thicknesses follow a long-tailed distribution --L\'evy-type distribution. Based on recent predictions made for 1D coherent transport with L\'evy-type disorder, we show numerically that for a system of length $L$ (i) the average $\propto L^\alpha$ for $0 \propto L$ for $1\le\alpha<2$, $\alpha$ being the exponent of the power-law decay of the layer-thickness probability distribution; and (ii) the transmission distribution $P(T)$ is independent of the angle of incidence and frequency of the electromagnetic wave, but it is fully determined by the values of $\alpha$ and $$.Comment: 4 pages, 4 figure

Time delay in 1D disordered media with high transmission

We study the time delay of reflected and transmitted waves in 1D disordered media with high transmission. Highly transparent and translucent random media are found in nature or can be synthetically produced. We perform numerical simulations of microwaves propagating in disordered waveguides to show that reflection amplitudes are described by complex Gaussian random variables with the remarkable consequence that the time-delay statistics in reflection of 1D disordered media are described as in random media in the diffusive regime. For transmitted waves, we show numerically that the time delay is an additive quantity and its fluctuations thus follow a Gaussian distribution. Ultimately, the distributions of the time delay in reflection and transmission are physical illustrations of the central limit theorem at work

Los signos del arte II

Dentro del marco de inclusión en el que las universidades colombianas deben asumir, se busca crear mecanismos que pluralicen la información y el acceso a ella. En este caso específico se pretende acercar a la población sorda, gestionando elementos que faciliten el aprendizaje en las Artes Visuales. Por medio de un diccionario virtual que recopilará en su función primordial, un banco de señas y palabras pertenecientes a la historia, técnicas y demás vocablos pertenecientes a las Artes, facilitando así los procesos de aprendizaje, el tiempo de interpretación y mejorando el vocabulario adquirido, tanto para el estudiante sordo, como para el intérprete, estudiante general y/o profesor que desee acercarse y compartir experiencias. El proyecto construyó en lenguaje de señas las correspondientes a los principales artistas estudiados en el programa de Artes, a partir de un proceso lógico en la escala de construcción que exige el lenguaje que ocupa a este trabajo. Por tanto en el presente documento se precisarán términos ajustados con gestos y movimientos de las manos con significados coherentes de aquellos, en un esfuerzo conjunto de saberes y competencias

Dolor abdominal agudo secundario a la ruptura de tumor de Wilms: reporte de caso

El tumor de Wilms es el tumor renal maligno más común en la edad pediátrica y su ruptura es un evento raro. Se presenta el caso de un paciente de 4 años de edad con un cuadro de dolor abdominal agudo, asociado a la presencia de masa palpable en flanco izquierdo; de acuerdo a la tomografía computarizada tomada, se muestra un tumor en mitad inferior del riñón izquierdo además de la presencia de líquido subhepático, periesplénico y en cavidad pelviana. Se realizó laparatomía de emergencia y nefrectomía radical del riñón izquierdo. El estudio anatomopatológico del tumor mostró nefroblastoma.Palabras clave: Tumor de Wilms, Hemoperitoneo, Dolor abdomina

Identidad, resistencia y cultura juvenil en la escuela

Este trabajo de grado tiene como eje principal de estudio la escuela como institución moderna, y su relación con las diferentes manifestaciones juveniles a partir de los conceptos de adscripción identitaria, cultura juvenil, y resistencia.Licenciado (a) en Educación Básica con Énfasis en Humanidades y Lengua CastellanaPregrad

CARCINOMA EPIDERMOIDE ASOCIADO A LA INFESTACIÓN CRÓNICA POR HABRONEMA MUSCAE EN UN CABALLO DE RAZA PINTO: REGISTRO DE UN CASO EN VENEZUELA

An 8 year old male Pinto horse (Equus caballus) had a history of chronic exudative nodular balanopostitis complicated by secondary bacterial infection dating back to 4 years. Severe chronic wasting, oliguria, stranguria, polydipsia and lymphoadenomegaly of bubos femurales and pre-scapular areas were noted. Euthanasia was performed. Later necropsy was performed systematically by the techniques described for horses. Tissue sections were taken for histopathological examination and were processed by conventional methods. Fecal samples were taken for parasitological studies. Gross examination revealed severe chronic wasting, and exudative balanoposthitis with severe chronic secondary bacterial infection. Evidenced hydroperitoneum lymphoadenomegaly of mesenteric nodes were also observed. Histological sections showed severe chronic balanoposthitis, with focal cell proliferation of squamous cell with abundant spin cells acanthosis, pleomorphism, nuclear hyperchromasia, anaplasia, typical mitotic figures, and atypical consistant presence of abundant pearls corneas. In some areas, granulomas were observed with parasite forms of the genus Habronema. Parasitological results were consistent with eggs of Habronema muscae. In conclusion, the clinical history, and macroscopic and histological findings demonstrate a syndrome of chronic balanopostitis and metastatic squamous cell carcinoma.Se remite un caballo (Equus caballus), sexo macho, de raza Pinto y 8 años de edad. Con historia de balanopostitis nodular exudativa crónica complicada con infección bacteriana secundaria data de 4 años. Emaciación crónica severa. Oliguria, estranguria y polidipsia. Linfadenomegalia de nódulos linfáticos inguinales y femurales preescapulares. Se le practicó eutanasia. Posteriormente se le prácticó necropsia por las técnicas sistemáticas descritas para equinos. Se tomaron secciones de tejido para estudio histopatológico y fueron procesadas por los métodos convencionales de procesamiento histológico. Fueron tomadas muestras de heces para estudios parasitológicos. El examen macroscópico reveló emaciación crónica severa. Balanopostitis exudativa crónica severa con infección bacteriana secundaria. Se evidencio hidroperitoneo marcado. Linfadenomegalia de nódulos mesentéricos. Los cortes histológicos evidenciaron: Balanopostitis crónica severa, con focos de proliferación de células escamosas espinocelulares con abundante acantosis, pleomorfismo, hipercromasia nuclear, anaplasia, figuras mitóticas típicas y atípicas constantes, presencia de perlas corneas abundantes. En algunas zonas se observaron granulomas con formas parasitarias tipo Habronema. Los resultados del estudio coprológico fueron consistentes con huevos de Habronema muscae. En conclusión: la historia clínica, los hallazgos macroscópicos e histológicos evidencian un síndrome de balanopostitis crónica y carcinoma epidermoide metastásico

Effects of Andreev reflection on the conductance of quantum-chaotic dots

We investigate the conductance statistics of a quantum-chaotic dot--a normal-metal grain--with a superconducting lead attached to it. The cases of one and two normal leads additionally attached to the dot are studied. For these two configurations the complete distribution of the conductance is calculated, within the framework of random matrix theory, as a function of the transparency parameter of the Schottky barrier formed at the interface of the normal-metal and superconducting regions. Our predictions are verified by numerical simulations.Comment: 8 pages, 7 figure

Vigilancia epidemiológica incompleta de la epidemia de dengue-2 en Ibagué, Colombia, 1995-1997

From April 1995 through November 1997 a dengue epidemic occurred in Ibagué (400,000 population), Colombia, where 3,419 cases were reported and DEN 2 virus was isolated from seven patients. A sero-survey conducted in 1996 found evidence of previous dengue infection in 9.6% of the population, indicating that many infections had not been reported. The dengue infections occurred in all age groups, but children under five years of age were most frequently infected. Forty-five percent of this Ibagué population were born after the re-appearance of dengue in Colombia in 1972, but have never been infected with dengue virus. Most of the cases reported as dengue hemorrhagic fever did not fulfill the current case definition. Aedes aegypti larvae were found in 19% of dwellings surveyed, most often in uncovered low tanks used for water storage. Many residents were not acquainted with the domestic nature of the mosquito vector. Health workers attributed the failure of the dengue control programs to lack of leadership and other administrative problems.Desde abril de 1995 a noviembre de 1997 ocurrió una epidemia de dengue en Ibagué, Tolima (400.000 habitantes), Colombia, en la cual se notificaron 3.419 casos y se aisló virus dengue 2 en el suero de 7 pacientes. En una encuesta serológica realizada en 1996 se encontró evidencia de infección anterior por dengue en 9,6% de la población, lo cual indica que muchas infecciones no se habían reportado. Las infecciones recientes del dengue ocurrieron en todos los grupos de edad, pero los niños menores de cinco años fueron más frecuentemente infectados. 45% de éstos, que nacieron después de la reemergencia del dengue en Colombia en 1972, nunca habían sido infectados con virus del dengue. La mayoría de los casos notificados de dengue hemorrágico no satisfacían la definición actual de caso. En el estudio entomológico se encontraron larvas en el 19% de las viviendas examinadas, la mayoría de las veces de Aedes aegypti en albercas destapadas, donde muchos residentes no entendían la naturaleza doméstica del mosquito vector. El personal de salud fue entrevistado y atribuyeron la falla de los programas de control del dengue a la carencia de dirección y a otros problemas administrativos

Entrepreneurship Networks against COVID-19

As of May 2022, the pandemic has limited opportunities for entrepreneurs. The objective of the study was to establish the networks of opportunities, motives, dispositions, ethics, pressures, challenges, reputation, images, identities and behaviors related to entrepreneurship in the face of the health and economic crisis. A documentary, cross-sectional and exploratory study was carried out with a selection of sources indexed to international repositories: Scopus, JCR, WoS, Latindex, Redalyc, Scielo and Frontiers. A search was made for the keywords of opportunism, optimization, innovation and entrepreneurship. The summaries corresponding to the pandemic period from November 2019 to May 2022 were considered. A structure of relationships between nodes and edges was found that suggests a neuronal learning that went from the dimension of pressure in the face of the pandemic to entrepreneurial identity. The centrality parameters that measure the distance between edges and nodes suggest that the dispositions are structured according to this principle of proximity. The grouping coefficients that indicate the structuring of the edges and nodes according to their dimensions suggest that the network is reconfigured from process innovation and resourcs optimization. The structure measure reflects the pressure concentration as the network input and the identity dimension as the network output. The centrality parameters that measure the distance between edges and nodes suggest that the dispositions are structured according to this principle of proximity. The grouping coefficients that indicate the structuring of the edges and nodes according to their dimensions suggest that the network is reconfigured from process innovation and recurss optimization. The structure measure reflects the pressure concentration as the network input and the identity dimension as the network output. In this way, the present study found a central and grouped structure in two dimensions of pressure and identity of entrepreneurship in the face of COVID-19 Delimitation to three dimensions of analysis corresponding to opportunities, optimizations and innovations is recommended